<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
  <div class="he">
    <p><input type="checkbox" name="" id="">两周内自动登录</p>
    <p class="qw" style="display: none;">测试</p>
  </div>
</body>
</html>
<style>
    .he{width: 300px;
    height: 40px;
        margin: 0 auto;
    }
</style>
<script>
    var gai=document.querySelector(".he")
    var qw=document.querySelector(".qw")
    gai.onmouseover=function(){
        qw.style.display="block"
    }
    gai.onmouseout=function(){
        qw.style.display="none"
    }
</script>